Who Really Owns the Ocean? How nations, corporations, and global institutions compete to govern the ocean

If the ocean is now being treated as the next major economic frontier, then we have to ask: who actually governs the space where all this investment is happening? In our previous blog we explored how money is pouring into the ‘blue economy’. But while the ocean is attracting trillions in investment, it remains one of the most politically complex spaces on Earth. Understanding who controls the ocean, and who is accountable when things go wrong, is essential to understanding the future of blue finance itself.

“How inappropriate to call this planet Earth when it is quite clearly Ocean.”

Arthur C. Clarke.

The ocean covers over 70% of the Earth, helps regulate the climate, absorbs vast amounts of carbon dioxide, and supports global food production and supply, trade and economies, but one major question remains: who actually owns the ocean?

At first glance the answer seems obvious. Countries control their coastlines, ships sail under national flags, and companies can only fish or drill in certain waters. But much of the ocean lies beyond national jurisdiction. Beyond coastal boundaries are the High Seas, international waters shared collectively through international law.

This makes the ocean one of the world’s largest global commons: spaces that everyone depends on, but no single country owns. As our cascading crises such as climate, overfishing, deep-sea mining and geopolitical competition intensify, governing this shared space has become increasingly difficult. Today nations, corporations and international organisations are all competing to shape the future of the ocean, often with very different priorities.

Can anyone actually own the ocean?

The idea of “owning” the ocean is far more complicated than owning land. Ocean governance is based less on ownership and more on sovereignty and jurisdiction: the rights countries have to control activities in different marine areas. Under the United Nations Convention on the Law of the Sea (UNCLOS), coastal states have authority over waters close to their shores. Closest to land are territorial waters, extending up to 12 nautical miles offshore, where states exercise sovereignty similar to on land.

Beyond this are Exclusive Economic Zones (EEZs), extending up to 200 nautical miles offshore. Here countries have special rights to access marine resources such as fish, oil and gas. Anything beyond EEZs is considered the High Seas, where no single country can claim ownership.

These distinctions are really important to understand because the ocean has valuable resources, critical trade routes and increasingly strategic locations. Much of global politics now depends on where one country’s jurisdiction ends and another begins.

Who makes the rules?

Because the ocean crosses borders, governance depends on treaties, institutions and international cooperation. At the centre of this is UNCLOS, the legal framework governing the ocean. Signed in 1982, it established rules around maritime boundaries, navigation rights, environmental responsibilities and seabed resources.

Other actors are involved too, The International Maritime Organization (IMO) sets standards for shipping safety and marine pollution, while the International Seabed Authority (ISA) oversees potential seabed mining in areas beyond national jurisdiction. Ocean governance is therefore heavily dependent on cooperation and voluntary compliance, and, as a result enforcement is often uneven or weak. Illegal fishing vessels continue operating across borders, marine pollution spreads between countries, and political interests frequently outweigh collective environmental responsibility. The ocean is shared, but political power remains divided.

Lessons from fisheries collapse

One of the clearest examples of ocean governance failure was the collapse of Atlantic cod fisheries in the North Atlantic. While the cod collapse occurred largely within national jurisdictions, it highlighted the wider difficulties of balancing scientific advice, economic interests and the need for marine protection. Industrial fishing expanded rapidly during the mid-20th century with the introduction of factory trawlers capable of catching fish at unprecedented scales, and travelling further distances with the availability of onboard blast freezers. Disputes over fishing rights during the “Cod Wars” between Iceland and the UK instigated the later development of Exclusive Economic Zones.

Despite growing scientific warnings during the 1980s, overfishing continued. In 1992 Canada officially closed the Northern Cod Fishery after stocks collapsed by around 99%, causing major economic and social disruption.

The cod collapse became one of the world’s most well-known examples of how overfishing, weak governance and short-term economic priorities can combine to drive ecological and economic collapse. If you would like to read more on this issue I recommend reading ‘Cod: A Biography of the Fish That Changed the World’ by Mark Kurlansky.

The High Seas Treaty

More recently, countries have attempted to strengthen protections for areas beyond national jurisdiction through the Biodiversity Beyond National Jurisdiction (BBNJ) Agreement, commonly known as the High Seas Treaty. Following decades of negotiations, the treaty entered into force in 2026 after enough countries formally ratified the agreement. Before the agreement, nearly half the planet’s surface lay beyond national jurisdiction without a comprehensive framework for biodiversity protection. BBNJ aims to create mechanisms for marine protected areas, environmental impact assessments and greater international cooperation across the High Seas.

Who Is competing for the ocean?

The ocean is also an economic and geopolitical space. Around 80-90% of global trade moves by sea, meaning shipping routes and maritime access remain strategically vital. At the same time, countries are increasingly interested in marine resources including fisheries, offshore energy and seabed minerals used in technologies associated with the energy transition. Competition is especially visible in contested regions such as the South China Sea, where countries including China, Vietnam and the Philippines claim overlapping maritime zones. The region is strategically important because of shipping routes, fisheries and potential energy reserves. These disputes reveal the tension between national interests and international law. Countries may agree to international frameworks like UNCLOS while still disagreeing over how rules should be interpreted or enforced.

Corporations also play a powerful role in the ocean economy. Global shipping companies move goods across international waters, industrial fishing fleets operate at enormous scales, and energy corporations continue offshore oil and gas extraction. Meanwhile some companies are exploring the possibility of deep-sea mining for minerals such as cobalt and nickel. Collectively these industries form a major part of the growing “blue economy”. But they also raise difficult questions around sustainability, accountability and environmental risk. Who is responsible when environmental damage occurs across multiple jurisdictions? And how do we balance economic growth with ecological protection?

The ocean doesn’t respect borders

Plastic pollution has become one visible symbol of the crisis, with millions of tonnes entering marine environments every year. But pollution is only one part of a much larger challenge.

Overfishing continues to threaten fish populations and marine ecosystems, while habitat destruction, chemical runoff and climate change intensify pressures on already vulnerable environments. These problems do not respect borders. Carbon emissions from one country affect the entire ocean, while plastic waste entering rivers inland can eventually reach international waters. Fish populations also migrate across jurisdictions regardless of political boundaries.

Responsibility is therefore interconnected, even if it is not equally shared. Wealthier industrialised nations have historically contributed most to greenhouse gas emissions and industrial pollution, while many of the most severe consequences are being experienced by smaller coastal and island nations with fewer resources to adapt. These inequalities reveal the broader challenge of global cooperation: who should bear responsibility for protecting shared spaces, and who should pay the costs?

Can the ocean ever be governed fairly?

As environmental pressures and competition for marine resources intensify, many experts argue existing governance systems are struggling to keep pace. Fragmentation remains one of the biggest challenges. Different institutions regulate different activities with overlapping responsibilities and inconsistent enforcement.

Deep-sea mining illustrates this tension clearly. Supporters argue that minerals found on the seabed may be important for technologies linked to the energy transition. Critics warn that mining poorly understood deep-sea ecosystems could cause irreversible damage before scientists fully understand the consequences. international efforts such as the expansion of marine protected areas demonstrate both the possibilities and limitations of cooperation. While governments are increasing commitments to protect marine environments, enforcing protections across the High Seas remains difficult. There is growing recognition that ocean governance cannot rely solely on governments. Businesses, communities, scientists and wider society all influence how marine resources are used and protected.

The future of the global commons

The question of who owns the ocean has no easy answer.  Some parts fall under national jurisdiction, but much of the ocean belongs collectively to humanity. The larger challenge is not anything to do with ownership, but governance.

The ocean connects societies, economies and ecosystems across the globe, but the systems designed to manage it remain fragmented and uneven. As climate risk accelerates and competition for marine resources grows, the future of the ocean will depend not only on international law but on whether countries, corporations and institutions can cooperate effectively.

Fundamentally, the ocean’s future is tied closely to humanity’s own. This is why ocean literacy matters.

At a time when information is widely available, many people still feel disconnected from how the ocean influences climate, economies and daily life. Building greater public understanding is about enabling better decisions across society. No country alone can protect the ocean, and no corporation can sustainably profit from a collapsing marine ecosystem. The ocean connects us all. The question now is whether humanity can learn to govern this shared space before the pressures placed upon it become irreversible.

 Written by Alana Wilson (with editorial direction from Leanne Hepburn)